Adropion, Pilato, 1987

Gąsiorek, Piotr, Blagden, Brian, Morek, Witold & Michalczyk, Łukasz, 2024, What is a ‘ strong’ synapomorphy? Redescriptions of Murray’s type species and descriptions of new taxa challenge the systematics of Hypsibiidae (Eutardigrada: Parachela), Zoological Journal of the Linnean Society 202 (1), pp. 1-63 : 12-13

Taxonomic key to the genus Adropion and species of Diphascon lacking a DABT

Remark: Adropion gani requires further investigation (see above) in order to ascribe it to the correct genus (i.e. a new genus or Pilatobius ). Therefore, it is excluded from the key, together with A. marcusi sp. dub. Note that although D. greveni and D. mauccii Dastych & McInnes, 1996 belong within Diphasconinae ( Tumanov and Tsvetkova 2023) , they cannot be distinguished morphologically from Adropion based on the currently recognized taxonomic criteria and are thus included in the key.

1. Macroplacoids granular ............................................................................................................................................................................... 2

– Macroplacoids bar-shaped .......................................................................................................................................................................... 4

2. Internal bars I–III present ......................................................................................................................................... Adropion gordonense

– Internal bars I–III absent ............................................................................................................................................................................. 3

3. Macroplacoid length sequence 1 <2 <3, dorsal granulation absent ............................................................... Adropion linzhiensis

– Macroplacoid length sequence 2 <1 <3, dorsal granulation present .......................................................... Adropion afroglacialis

4. Three macroplacoids present ...................................................................................................................................................................... 5

– Two macroplacoids present ........................................................................................................................................................................ 9

5. Both microplacoid and septulum present ................................................................................................................................................ 6

– Only microplacoid or septulum present .................................................................................................................................................. 7

6. Bases of external claws I-III with indented bases, pt of SSIP = 67–75% ............................................................. Diphascon greveni

– Bases of external claws I-III with smooth bases, pt of SSIP = 64–65% ................................................................... Adropion onorei

7. Microplacoid absent, septulum present .................................................................................................................... Diphascon mauccii

– Microplacoid present, septulum absent ................................................................................................................................................... 8

8. Eyes present ................................................................................................................................. Adropion ommatophorum comb. nov.

– Eyes absent ....................................................................................................................................................................... Adropion scoticum

9. Cuticular bars absent (the edges of external pulvini I–III may be faintly visible) .............................................. Adropion belgicae

– Median and internal cuticular bars I–III and posterior bars between bases of claw IV present ...................................................... .................................................................................................................................... Adropion diphasconiellum comb. nov. et stat. rev.